Engineered TCR therapy targeting lipid antigens in AML 2306228

Abstract Introduction Acute myeloid leukemia (AML) is the most common form of adult leukemia and has a poor prognosis with a 5-year overall survival of ∼30%. While CAR-T has revolutionized the treatment of other hematological malignancies, it has been difficult to replicate this same success in AML. Healthy myeloid cells often share expression of putative AML targets and have led to significant toxicity in clinical trials. These challenges necessitate examining unexplored target antigens with higher cancer specificity, such as lipids. Methods This project aims to target lipid antigens presented by CD1d, an MHC Class 1-like molecule that presents lipid antigens to unconventional T cells such as iNKT cells. We aim to develop a lipid-targeting cell therapy for AML by engineering conventional T cells with a CD1d-targeting TCR derived from iNKT cells. These engineered T cells (herein called CD1d-targeting T cells) were co-cultured with CD1d+ AML cell lines with a-GalCer, a canonical iNKT agonist, or DMSO as a vehicle control for up to 72 hours and at varying effector: target ratios. Cells were analyzed or cytotoxicity via flow cytometry and supernatant was collected for ELISA. Results CD1d-targeting T cells demonstrated robust cytotoxicity against CD1d+ AML cell lines in the presence of a-GalCer. CD1d KO cells (THP-1) showed no killing in the presence of a-GalCer or DMSO. Cell lines with higher CD1d expression (OCI-AML3) displaying targeted killing without the presence of a-GalCer. IFN-y ELISA results corroborate results from our killing assays and show pronounced IFN-y production in culture conditions that have high CD1d expression and/or presence of a lipid antigen. Conclusion Our engineered T cells showed CD1d-specific killing that was dependent on CD1d expression, and in cases of high CD1d expression, may be dependent on endogenously self-lipids found in AML cells. Further work will be done to identify putative lipid antigen targets and establish in vivo efficacy and safety our CD1d-targeting T cells. Funding Source n/a Topic Categories Vaccines and Immunotherapy (VAC)